Since Start.me rolled out the new version of their website a few days ago, HTTPS-Everywhere seems to "block" some icons (these seem to be some kind of font, not an image):

This is how it looks like when I deactivate "Start.me (partial)":

I also tried it with a new profile (I'm using Firefox 37.0.1), but it also occurs there. Here is an example page where this can be reproduced:

http://www.start.me/p/W1kloV/startpage-us

I hope this will be fixed.